Normally‐off top‐gate self‐aligned field‐effect transistor using crystal InO _<i>x</i> with field‐effect mobility of around 100 cm ² /vs

Abstract In this study, we designed and fabricated a crystal InO x (crystal IO)‐based field‐effect transistor (FET) on a 3.5th generation glass (600 mm × 720 mm) substrate line. The FET exhibits high field‐effect mobility exceeding 90 cm 2 /Vs, an on‐state current higher than that of a low‐temperature polysilicon (LTPS)‐based FET, normally‐off characteristics, an extremely low off‐state current, a high breakdown voltage, and high reliability. The synthesized crystal IO is less susceptible to grain boundary scattering and exhibits a small variation in grain size on the substrate plane. The crystal IO‐based FET exhibits a small variation in electrical characteristics. Combining our organic light‐emitting diode (OLED) patterning technology with a display backplane based on crystal IO, we obtained an 8.3‐in. 8K4K OLED display with high luminance and low power consumption. These results demonstrate that crystal IO can replace LTPS and low‐temperature polycrystalline oxide, which have been mainly used in the backplanes of small‐ and medium‐sized displays, and that backplanes of displays of all sizes can be completely oxide based.